Carton sealed by internal end flooding



y 10, 1956 F. D. BERGSTEIN 2,754,044

CARTON SEALED BY INTERNAL END FLOODING Filed Jan. 15, 1953 QTTORNEYS.

CARTON SEALED BY INTERNAL END FLOODING Frank David Bergstein, Hamilton, Ohio, assignor to The Eergstein Packaging Trust, a trust composed of Robert M. Bergstein and Frank D. Bergstein, trustees Application January 15, 1953, Serial No. 331,441

4 Claims. (Cl. 229-31) This invention has to do with paperboard containers which are moisture-tight, liquid-tight, or gas-tight as desired, and which comprise in essence a knock-down paperboard carton which may be shipped and stored in the flat condition.

In my Patent No. 2,604,252 entitled Tight Carton, I have taught the provision of a knock-down carton having the desired proofed characteristics as to its body portion. The carton comprises enclosing body walls in articulation and end closure flaps, the body walls being tubed by means of a glue flap carried by the free edge of one of the body walls. Upon erection of the tubular body the closure flaps are closed across one end of the carton, whereupon the closed carton end is sealed interiorly by means of thermoplastic sealing substance deposited on the closed end of the carton in a quantity sufiicient to provide a solid block of sealing material extending continuously across the end of the carton from wall to wall, thereby completely covering all inwardly exposed surfaces of the folded flaps and sealing all interstices therein. Where but one end of the carton is to be sealed in the manner just described, a pipe or nozzle is introduced into the carton through the open end thereof to deposit the proofing material on the closed end of the carton. Where it is desired to proof both ends of the carton, an opening may be provided through one of the end closures through which the sealing substance is introduced into the carton, whereupon the opening itself is closed by plug-like member; or as taught in my Patent No. 2,543,757, entitled Sealed Carton and Method, an opening may be provided in one of the body walls of the carton through which a pipe or nozzle is inserted to introduce the sealing material into the carton, the opening in the carton body wall being subsequently sealed.

Where the sealing substance covering one end of the carton is to be introduced through an opening formed in the end closure at the opposite end of the carton, l have found it desirable to provide a plug-like fitting adapted to close the opening during sealing of the first end of the carton, thereby preventing the sealing substance from covering the opening. Upon hardening of the sealing substance the plug-like element is removed and a nozzle inserted through the opening to effect the seal of the remaining end of the carton. Alternatively, the opposite end of the carton, i. e., the end not having an opening therein, may be sealed first, whereupon a plug-like fitting having downwardly directed nozzle means associated therewith may be inserted through the opening and the seal of the remaining end effected. Again, in accordance with the teachings of my Patent 2,549,048 entitled Liquidtight Carton and Method, the end of the carton having the opening therein may be provided with an overlying flap portion covering the opening from the outside. Sealing substance is introduced into the carton from the opposite, open end thereof to cover the end of the carton and the opening therein, the sealing substance bonding to the overlying flap. Upon solidification of the sealing substance, the overlying flap is lifted so as to nited States Patent 6 f 2,754,044 Patented July 10, 1956 ice fracture the casting of sealing substance along the line as determined by the periphery of the opening, whereupon the opposite end of the carton is closed and sealed by means of a nozzle introduced through the opening. The opening will, of course, be reclosed by the pluglike portion carried by the overlying flap and upon reclosure of the flap heat may be applied thereto to fuse the plug to the remainder of the end casting.

While all of the above patents provide an absolute seal for the carton ends, the proofness of the cartons will be no better than the proofness of their body walls. Proofness of the walls as such is generally attained by treating the blank, or the paperboard from which the blank is made with a suitable proofing substance, of which there are many. The most common and least expensive mode of treatment comprises coating the board on either one or both surfaces with a film or layer of proofing material such as wax or resin. While a coating or coatings of proofing material adequately proofs the surfaces or faces of the board, difiiculty arises in proofing the edges of the board; and this difiiculty manifests itself in the proofing of the exposed interior edge of the longitudinal seam created by the formation of a conventional die cut paperboard blank into a tubular carton structure. The interior edg of the longitudinal seam, being untreated, will wick or absorb liquids as well as permit the exchange of atmos phere from one side of the carton to the other; and unless this untreated edge is properly covered and sealed, a tight and proofed condition of the container cannot be attained.

It is therefore, a principal object of my invention to attain proofness in collapsible structures both as to the end walls and body walls thereof, and particularly as to the exposed edges of the longitudinal scam in the carton body.

It is an object of my invention to attain completely proofed carton structures by less complicated procedures and equipment and with fewer operations.

It is a further object of my invention to provide proofed carton structures in which the proofing material is confined to the inside of the carton and does not in any way interfere with its external appearance.

It is a still further object of my invention to provide a procedure wherein both the ends of the package and the longitudinal seam thereof may be proofed in a single proofing operation which is both easy to perform and economical and which can be carried out by the carton user at a minimum of expense.

These and other objects of my invention which will become apparent hereinafter or will be apparent to the skilled worker in the art upon reading these specifications, 1 accomplish by that construction and arrangement of parts and by those procedures of which I shall now describe an exemplary embodiment. Reference is now made to the accompanying drawings wherein:

Figure 1 is a plan view of a blank for a carton to be used in accordance with my invention.

Figure 2 is a similar view showing the blank in tubed condition.

Figure 3 is a perspective view showing the tubed blank in erected condition with certain of the end closure flaps in infolded condition.

Figure 4 is a partial perspective view of the erected carton with the top end closure flaps in folded condition.

Figure 5 is a vertical longitudinal section showing a first step in the end sealing of the carton.

Figure 6 is a sectional view taken along the line 6-6 of Figure 5.

Figure 7 is a partial vertical longitudinal section showing a succeeding step in sealing the carton.

Figure 8 is a sectional view taken along the line 88 of Figure 7.

Figure 9 is a vertical longitudinal section similar to Figure 5 showing the sealing of the opposite end of the carton.

In the practice of my invention, I provide a knockdown carton having the desired proofed characteristics as to its body portion. I then eifect an end closure and seal, the latter by operation effective on the inside of the package structure. Since the carton structure will find utility in various fields of use, the closure and seal just referred to may be made on one end of the carton only and the other end closed in some other fashion. Or both ends of the cartonmay be closed and sealed by operation such as those set forth.

Referring now to Figure l of the drawings, I have therein illustrated a carton blank having body walls 1, 2, 3, and 4, and a glue flap 5 in articulation in the order named along the usual longitudinal score lines. The top ends of the body walls are provided with closure flaps 6, 7, 8 and 9 inclusive, articulated to the walls along the transverse score line 10, and the bottom edges of the body walls are provided with closure flaps 11, 12, 13 and 14 inclusive, articulated to the walls along transverse score line 15.

At the upper end of the carton, the closure flaps 7 and 9 may be short flaps, the flap 9 additionally having an opening 16 therein adapted to coincide with mating openings 17 and 18 in the flaps 6 and 8. At the other end of the carton the flaps 11 and 13 may be short flaps, whereas the flaps 12 and 14 are of full size.

The blank of Figure 1 will be tubed in the usual fashion by folding it on intermediate longitudinal score lines with the adhesive union of the glue flap 5 to the body wall 1. As seen in Figure 2 the glue flap 5 will lie to the outside of the body wall 1. This construction constitutes the free edge of the body wall 1 as the interior exposed edge of the longitudinal seam, and it will be noted that this edge lies along the corner of the carton. The carton may be shipped to the user in the collapsed tubular form as shown.

The user will erect or square up the carton body and will proceed to effect the end closure and seal. This may be done by folding the flaps 7 and 9 at the top of the carton, next the flap 6, and finally the flap 8. These flaps may be adhesively secured together and the adhesive may be applied during the operation of folding. The mating openings 16, 17 and 18 will come together when the end flaps are infolded to form a filling opening through the end of the carton.

A proofed condition of the end closure and the longitudinal seam may be obtained in the manner illustrated in Figure 5 with the use of the sealing means shown therein. The sealing means comprises a base or support 20 having an upstanding plug-like member 21 of a size to enter the opening in the carton closure and project somewhat within the carton. Preferably the base 2t} will be provided with a hinge 22 for pivoting movement of the base about a horizontal axis, and the base and the hinge may be carried by a moving chain or conveyor 23 where it is desired to handle the carton in a continuous, automatic operation. A nozzle 24 will be provided for the introduction of the sealing substance into the carton, and means (not shown) will be provided to tilt the base or support 20 and the carton to the position illustrated in Figure 5.

The carton will be placed on the support 20 with the closed end downwardly and the plug-like member 21 extending through the opening in the closed end thereof. The carton will be diagonally disposed on the support 26 in the manner best seen in Figure 6, with the edge or corner of the carton including the exposed edge of the longitudinal seam adjacent the axis of the hinge 22. Thus, upon tilting movement of the support 20 to the position illustrated in Figure 5, the corner or edge of the carton which includes the longitudinal seam will be inclined so as to form a trough along which sealing substance introduced into the carton at the top corner edge thereof will flow downwardly along the trough to the bottom of the carton. Thus, sealing material introduced into the carton through the nozzle 24 will flow downwardly along the edge of the carton forming a longitudinal head 25 of sealing material extending the full length 7 of the seam and completely covering and sealing the exposed edge thereof, the bead actually forming an imperforate barrier extending between adjacent side edges of wall panels 1 and 4. Thus the exposed edge of the seam is completely sealed and wicking or the exchange of atmosphere through the edge of the seam prevented.

Preferably the quantity of sealing substance introduced through the nozzle will also serve to cover and seal the end of the carton. As seen in Fig. 5, the excess material wi l form a pool 25 of sealing material at the bottom of the filled carton. Following the introduction of the sealing substance into the carton in the manner just described, the carton is then tilted to the vertical position, as seen in Figure 7, whereupon the pool 26 of sealing substance will flow across the closed end of the carton to form the layer or casting 27. The casting 27 will completely cover the end closure flaps of the carton and will extend from wall to wall thereof excepting, of course, for the area defined by the plug-like member 21. The casting 27 thus forms an imperforate seal across the end of the carton, and together with the longitudinal bead completes the proofing of the carton body walls and the one end closure.

Following the sealing of the longitudinal seam and the closed end of the carton in the manner just described, the opposite end of the carton will be closed and a seal effected across the inner end thereof by means of sealing material introduced into the carton through the opening in the first sealed end thereof, thereby completing the proofing of the carton structure. Alternatively, the end of the carton containing the filling opening may be first sealed in the manner taught in my above mentioned patents the carton being maintained in vertical position during the introduction of the sealing substance. Then, upon removal of the plug-like element and the closing of the remaining end of the carton, the carton may be treated in the maner illustrated in Figure 9, wherein a filling nozzle 30 having a curved end 31 is provided to introduce sealing substance into the carton adjacent the top edge thereof, the carton again being slanted or tilted with the edge including the longitudinal seam undermost so as to allow the filling material to flow downwardly along the edge to the bottom of the carton. As before, immediately following the introduction of the sealing material, the carton will be returned to the vertical position so as to distribute the sealing material across the bottom thereof.

While I have described my invention as it applies to an unlined paperboard carton, it will be apparent that the invention is equally applicable to a lined carton taught in my patent, No. 2,064,252, provided, of course, the longitudinal seam for the liner is formed with the exposed inner edge thereof at a corner of the carton. Also, it will be evident that where the longitudinal seam is to be sealed in the manner illustrated in Figure 9, wherein the nozzle is introduced through the opening in the carton end and the sealing material allowed to flow down the edge of the carton, it is preferable to form the longitudinal seam at the corner of the carton adjacent the filling opening.

I have found that the procedure just described provides an economical method for assuring absolute proofness of the longitudinal seam and requires but a slight additional amount of sealing material over that required to seal the carton ends. For example, in a carton of conventional dimensions for use as a container for milk, about one additional gram of sealing material is required to seal the edge of the longitudinal seam. This is about one-tenth of the amount of sealing substance necessary to form the end seals of the carton and is of negligible additional cost as compared to a pretreatment of the edges of the board.

Modifications may be made in my invention without departing from the spirit of it. Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a proofed paperboard carton, a tubular body including a longitudinal seam the inner edge of which lies along a corner edge of the tubular body in substantially abutting relationship to the carton body wall adjoining said seam, and a bead of sealing substance extending continuously along the entire length of the said corner edge and covering and sealing the inner edge of said longitudinal seam, said bead of sealing substance being formed in situ, bridging the corner edge of the carton and bonded to longitudinal edge portions of the carton body walls contiguous to said corner, the said bead of sealing substance being confined to the corner of the carton including said longitudinal seam, the said carton body being otherwise free of the said sealing substance.

2. A proofed paperboard structure comprising a paperboard carton having enclosing body walls in articulation and closure flaps articulated to at least one end thereof, said enclosing body walls being tubed with a longitudinal seam the exposed inner edge of which lies along a corner edge of the carton body in substantially abutting relationship to the carton body wall adjoining said seam, said carton being in erected condition with the closure flaps closed across the end thereof and sealed interiorly across the closed end by an imperforate casting of thermoplastic sealing substance extending continuously across the end of the carton from wall to wall, said longitudinal seam being sealed by a continuous head of the said sealing substance which is integral with said end casting and extends continuously along the entire length of the said corner edge of the carton and covers and seals the exposed inner edge of the seam, said bead of sealing substance bridging the corner edge of the carton and bonded to the longitudinal edge portions of the carton body walls contiguous to said corner edge, said casting and said bead of sealing substance being formed in situ in the erected carton.

3. A method of making liquid-tight containers which comprises providing a tubular carton formed with a longitudinal seam having an interior edge lying along a corner edge of the carton body in substantially abutting relationship to the carton body wall adjoining said seam, and end closure flaps articulated to at least one end of said carton body, erecting said carton and closing the end closure flap across an end thereof, positioning the carton with the closed end lowermost and tilting it in the direction of the corner thereof including said longitudinal seam so that the said corner will serve as a trough, and introducing into said carton at the top of said corner a measured quantity of liquid sealing material sufficient to form a continuous bead extending along the entire length of the said corner and permitting said sealing substance to flow downwardly along said corner to form a continuous bead which bridges the corner of the carton and is bonded to longitudinal edge portions of the carton body walls contiguous to said corner, the measured quantity of sealing material being confined solely to the said corner of the carton body as it flows downwardly therealong.

4. A method of making liquid-tight containers which comprises providing a tubular carton formed with a longitudinal seam having an interior edge lying along a corner edge of the carton body in substantially abutting relationship to the carton body wall adjoining said seam, and end closure flaps articulated to at least one end of said carton body, erecting said carton body and closing the end closure flaps across an end thereof, positioning the carton with the closed end lowermost and tilting it in the direction of the corner thereof including said longitudinal seam so that the said corner will serve as a trough, and introducing into the carton from the top of the said corner a measured quantity of liquid sealing material suflicient to form a continuous bead extending along the entire length of the said corner and form a pool at the bottom thereof, and thereafter tilting the carton to an upright position so as to distribute the pool of liquid sealing material across the closed end of the carton to provide a casting of sealing substance extending continuously across the end of the carton from wall to wall, with the longitudinal seam sealed by the continuous head of sealing substance which is integral with the said casting and bridges the corner of the carton and is bonded to longitudinal edge portions of the carton body walls contiguous to said corner, the said measured quantity of sealing material being confined solely to the said corner of the carton as it flows downwardly therealong.

References Cited in the file of this patent UNITED STATES PATENTS 2,043,135 Wesselman June 2, 1936 2,335,865 Lanigan et a1 Dec. 7, 1943 2,496,043 Farrell Jan. 31, 1950 2,506,056 Bergstein May 2, 1950 2,549,048 Bergstein Apr. 17, 1951 2,604,252 Bergstein July 22, 1952 2,661,141 Zinn Dec. 1, 1953 

